• Title/Summary/Keyword: Incinerators

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The Characteristics of Mercury Emission from Municipal Solid Waste (MSW) Incinerator Stack (폐기물 소각시설 배가스에서의 수은 배출특성)

  • Lee Han-Kook
    • Journal of Environmental Health Sciences
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    • v.30 no.5 s.81
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    • pp.378-387
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    • 2004
  • This study was carried to investigate the emission characteristics of mercury from domestic and industrial MSW (municipal solid waste) incinerator stacks. The mercury concentration levels of flue gas from 32 MSW incinerators stacks selected were above the criteria level ($5{\mu}g/S\;m^3$). MSWI facilities exceeding the criteria levels in Korea are due to the poor units comparison of combustion chamber(CC)-cyclone(CY)-stack. So, the mercury from MSW incinerators stack were suspected to contaminate the natural system unless the MSW incinerators were properly controlled. Mean-while, the relationship between mercury concentration and temperature of flue gas in MSW incinerator stacks were examined at two temperature ranges (Group A : $29.85{\sim}327.63^{\circ}C$, Group B : $446.9{\sim}848.15^{\circ}C$). The mercury concentration in flue gas with high temperature range was higher than that of flue gas with low temperature rage. This mean that the temperature of flue gas plays an important role in mercury control in MSW incinerator. The emission characteristics oi mercury was also evaluated by using the correlation matrix between the mercury and NOx, $PM_{10}$, moisture (MO.) at both low temperature and high temperature flue gas ranges. The mercury concentration was mainly affected by NOx, $PM_{10}$. moisture (MO.) at low temperature range, while the mercury concentration at high temperature flue gas was mainly affected by NOx, moisture (MO.). From these results, it was suggested that the temperature of cooling system and the air pollution control device should be properly regulated in order to control mercury of flue gas in MSWI incinerator.

Emission Characteristics of PMs and Heavy Metals from Industrial Hazardous Waste Incinerators (산업 폐기물 소각시설의 입자상 물질 및 중금속의 배출특성)

  • 유종익;이성준;김기헌;장하나;석정희;석광설;홍지형;김병화;서용칠
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.3
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    • pp.213-221
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    • 2002
  • The emission characteristics of particulate matter (PMs) and heavy metals from hazardous industrial wast incinerators were investigated. The particle size distribution (PSD) of PM-10 showed different patterns for two tripes of incinerators; stoker and rotary kiln. However both types showed bimodal form at inlet of air pollution control devices (APCD) and each peak (mode) is located at smaller than 1 ${\mu}{\textrm}{m}$ and near 10 ${\mu}{\textrm}{m}$. It could explain the growth of fine PM by nucleation/coagulation/condensation of metal vapors for fine mode. The PSD of PM-10 after APCD was also influenced by APCD types that had different collection mechanism, and both electrostatic precipitator and bag filter showed less collection efficiency for particles ranged from 0.2 to 0.4 ${\mu}{\textrm}{m}$ and led to a mode in the range of 0.2 to 0.8 ${\mu}{\textrm}{m}$. However the hag filter showed two modes of PSD, while the electrostatic precipitator had one peak. The PMs and heavy metals emission factors, the representative value of emission quantity for sources, for tested facilities were developed. The emission factor of uncontrolled total PM and PM-10 were 14.7 and 7.05 kg/ton waste, respectively. The emission factors from this study were a little bit different with those from US EPA AP-42. It may thus be appropriate to use these results in the course of developing national emission factors.

Discussion on the Practical Use of CFD for Furnaces;A Case of Grate Type Waste Incinerators (연소로 열유동 해석 방식과 결과 분석에 대한 고찰;화격자식 소각로의 사례)

  • Ryu, Chang-Kook;Choi, Sang-Min
    • 한국연소학회:학술대회논문집
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    • 2002.06a
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    • pp.85-94
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    • 2002
  • Computational flow dynamics(CFD) has been frequently applied to the waste incinerators to understand the flow performance for various design and operating parameters. Though it needs many simplifications and complicated flow models, the reasonability of its results is not fully evaluated. For example, the inlet condition is calculated from an arbitrarily assumed properties of combustion gas release from the waste bed, since the combustion in the bed is difficult to be predicted. In this study, the computational modeling and calculation procedures of CFD for the grate type waste incinerator were evaluated using comparative simulations. Though the assumption method on the generation of the combustion gas directly affected the temperature and gas species concentrations, the overall flow pattern was dominated by the secondary air jets. The gaseous reaction could be included by assuming the release of the products of incomplete combusion from the bed. However, the reaction effficiency cannot not be directly evaluated from the species concentration, since it is not possible to simulate the actual co-existence of fuel rich or oxygen rich puffs over the bed. In predicting the turbulence, the higher order model, such as Reynolds stress model, gave difference shape of local recirculation zones, but similar results was acquired from the standard $k-{\varepsilon}$ model. Introducing radiation model was required for accurate temperature prediction, but it also caused heat imbalance due to the fixed temperature of the inlet, i.e. the waste bed. Thus, the computational modeling procedures on incinerators and the analysis of the predicted results should be progressed carefully. Though not validated experimentally, current simulation method is capable of comparative evaluation on the flow-related parameters such as the furnace shape and secondary air injection using identical inlet conditions. Quantitative analysis using measures of the residence time and mixing is essential to compare the flow performance efficiently.

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Research Investigations at the Municipal (2×35) and Clinical (2×5 MW) Waste Incinerators in Sheffield, UK

  • Swithenbank, J.;Nasserzadeh, V.;Ewan, B.C.R.;Delay, I.;Lawrence, D.;Jones, B.
    • Clean Technology
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    • v.2 no.2
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    • pp.100-125
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    • 1996
  • After recycle of spent materials has been optimised, there remains a proportion of waste which must be dealt with in the most environmentally friendly manner available. For materials such as municipal waste, clinical waste, toxic waste and special wastes such as tyres, incineration is often the most appropriate technology. The study of incineration must take a process system approach covering the following aspects: ${\bullet}$ Collection and blending of waste, ${\bullet}$ The two stage combustion process, ${\bullet}$ Quenching, scrubbing and polishing of the flue gases, ${\bullet}$ Dispersion of the flue gases and disposal of any solid or liquid effluent. The design of furnaces for the burning of a bed of material is being hampered by lack of an accurate mathematical model of the process and some semi-empirical correlations have to be used at present. The prediction of the incinerator gas phase flow is in a more advanced stage of development using computational fluid dynamics (CFD) analysis, although further validation data is still required. Unfortunately, it is not possible to scale down many aspects of waste incineration and tests on full scale incinerators are essencial. Thanks to a close relationship between SUWIC and Sheffield Heat&Power Ltd., an extended research programme has been carried out ar the Bernard Road Incinerator plant in Sheffield. This plant consists of two Municipal(35 MW) and two Clinical (5MW) Waste Incinerators which provide district heating for a large part of city. The heat is distributed as hot water to commercial, domestic ( >5000 dwelling) and industrial buildings through 30km of 14" pipes plus a smaller pipe distribution system. To improve the economics, a 6 MW generator is now being added to the system.

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The Role of (Chloro-) Phenols in the Formation of Polychlorinated Dibenzofurans in Municipal Waste Incinerators

  • Ryu, Jae-Yong;Jang, Seong-Ho
    • Journal of Environmental Science International
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    • v.16 no.1
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    • pp.9-19
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    • 2007
  • Comparing predicted PCDF isomer patterns with those obtained from a municipal waste incinerator assessed the role of two-phenol condensation pathways in the formation of PCDFs. Complete PCDF homologue and isomer distributions were obtained from a Fluidized Bed Incinerator (FBI). Two-phenol condensation model, dependent only on the distributions of phenols, was developed to predict the PCDF congeners produced from phenol precursors. R-squared values from linear correlations are presented for the dichlorinated through hexa-chlorinated isomer distributions between measured and predicted. They range from 0.00: to 0.1 far the di-chlorinated through hexa-chlorinated isomer sets. Agreement between predicted and measured PCDF isomer distributions was very poor for all homologues. Two-phenol condensation pathways are not likely to be the pre-dominant pathways in the formation of PCDF in a FBI. However, dibenzofuran (DF) is likely to be produced from a condensation of two phenols. This work demonstrates the use of PCDF homologue and isomer patterns for testing PCDF formation mechanism from two-phenol condensation pathways in municipal waste incinerators.

PCDD/PCDFs Emission and Operating Conditions of Domestic MSW Incinerators (국내 도시 쓰레기 소각로에서의 운전조건과 다이옥신 배출량과의 상관관계에 관한 연구)

  • Yang, Won;Shin, Donghoon;Choi, Jinhwan;Choi, Sangmin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.12
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    • pp.1755-1762
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    • 1998
  • In order to minimize emission of polychlorinated dibenzo dioxins and polychlorinated dibenzo furans (PCDD/PCDFs) from municipal solid waste incinerators, it is important to maintain optimized operating conditions along with the system modification/improvement. Operating conditions of MSW incinerator make very complicated influence on formation of PCDD/PCDFs in each unit apparatus. For revealing these influences, concentrations of PCDD/PCDFs are measured from the stack and from the fly ash, while monitoring the plant operating conditions. The effects are grouped into 3 main categories, combustion conditions, de Novo synthesis effects, and adsorption/destruction effects in the flue gas treatment system. Interpretation of the results showed that de Novo synthesis effect, reformation by metalic catalyst, especially Cu in fly ash in the temperature range of $250{\sim}500^{\circ}C$, is found to influence most dominantly on the concentration of PCDD/PCDFs. A plausible mathmatical model for predicting concentration of PCDD/PCDFs is proposed, and discussed.